1. Field of the Invention
The present invention generally relates to methods and compositions related to the determination and use of white blood cell counts.
2. Description of Related Art
White blood cell counts are routine medical tests used to diagnose a variety of disease processes, to follow the progression of a disease, or to monitor the effect of medical treatment. Low levels of white blood cells are associated, for example, with bone marrow failure, cytotoxicity, liver disease, and lupus, whereas high levels are associated, for example, with infectious diseases, inflammatory diseases, and leukemia, Differential white blood cell counts are also useful medical tests. Specific lymphocyte populations are elevated, for example, in HIV-infected subjects. The absolute count of CD4+ lymphocytes, for example, is used to determine when to commence antiretroviral therapy in subjects with HIV, and the percentage of CD4+ cells is widely used to determine pediatric care and treatment.
There are 2.2 billion children in the world, 1.9 billion of them living in developing countries, and about half of that number, living in poverty. (UNAIDS/WHO, 2005) In 2003, 10.6 million children, worldwide died before they were five (this number represents the entire population of children under five of France, Germany, Greece and Italy). Children under 15 get infected with HIV at the rate of one every minute. Ninety percent of the more than 5 million children who have been infected were born in Africa. Meanwhile, the number of cases is rising in other parts of the world. In the worst-affected countries, AIDS is now the biggest single cause of death among the under 5s, and is threatening to reverse years of hard-won progress in reducing child mortality. Thus, needed in the art are means of testing and evaluating white blood cell counts using simple, inexpensive devices.
Current methodology used to complete medical diagnostics, as well as environmental monitoring and detection of bioterrorism-related agents often require large and expensive instruments and highly specialized personnel found only in certain hospitals, laboratories or government agencies. Furthermore, these instruments are often restricted to a limited number of applications. For example, in the area of medical diagnostics, each instrument is very specialized and designed either to measure protein levels or to analyze cellular matter but, typically, may never do both. Additionally, each system is capable of analyzing only a few of the relevant markers of a disease, therefore adding another component to an already tedious and time consuming process that can vary from hours to days. Long delays can be generated between the time of the initial visit, diagnosis, and administration of treatment, potentially having detrimental effects on the prognosis of the disease.